1. Field of the Invention
The present invention relates to an electronic component in which a cavity is provided between a substrate and a cover member, and a manufacturing method for the electronic component.
2. Description of the Related Art
International Publication No. 2009/078137 discloses a surface acoustic wave device having a wafer level package structure. In International Publication No. 2009/078137, interdigital transducer (IDT) electrodes are provided on a piezoelectric substrate. A frame-shaped support layer including resin surrounds the IDT electrodes. Via conductors penetrate the support layer. The via conductors are electrically connected to the IDT electrodes. Further, bumps are joined to upper ends of the via conductors.
After the support layer is formed, a cover member is formed to close openings of the support layer.
In actual manufacturing, the above-described laminated structure is formed and then cut into individual surface acoustic wave devices with a dicing machine. In International Publication No. 2009/078137, the support layer is located inside dicing lines. When in a form of a motherboard, a resin connecting portion is formed to connect adjacent support layer parts. This resin connecting portion connects long side portions and to connect short side portions of the support layer parts each shaped like a rectangular frame.
The resin connecting portion is provided adjacent to the via conductors to be joined to the bumps. This arrangement can cause microcracks to form near the bumps. After cutting, each surface acoustic wave device is mounted on a second substrate, which is used to form a WLP (wafer level package) structure or a circuit board by reflow. In this case, stress is applied immediately under the bumps, which can cause cracks to form from the microcracks. The cracks can extend to portions of the piezoelectric substrate present under the support layer or near the support layer.
Further, the cover member sometimes peels from the support layer in the cutting operation. For this reason, for example, when resin molding is further performed, resin may infiltrate inside the support layer.